


Siblings With Benefits

by EyesOnYou



Category: EXO (Band), Kpop - Fandom
Genre: Brother/Sister Incest, Cheating, Consensual Underage Sex, F/M, Fucking, Incest, Rough Sex, Semi-Public Sex, Sex, Sibling Incest, Twins, Underage Drinking, Underage Sex
Language: English
Status: In-Progress
Published: 2020-07-06
Updated: 2020-10-25
Packaged: 2021-03-04 21:20:09
Rating: Explicit
Warnings: Underage
Chapters: 3
Words: 4,302
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25103044
Author URL: https://archiveofourown.org/users/EyesOnYou/pseuds/EyesOnYou
Summary: Sehun and Serri are twins that benefit from one another in a very interesting way. That is until Sehun fucks up and Serri learns the hard way on how this can end up disastrous.
Relationships: Oh Sehun/Original Character(s), Oh Sehun/Reader
Kudos: 23





	1. Prologue

You might be asking yourself right now _'Serri, how did you end up like this?'_ , well my friend, even I don't know the answer to that question. 

Here I am. In front of my room watching the love of my life fuck my best friend on my bed. He is going all out with her, calling her a whore and slapping her tits. Her screams asking him for more and faster as my heart shatters into a million pieces.

Oh did I mention that the love of my life is actually my brother? My twin brother? No? Well he is. My twin brother, Sehun, is fucking my best friend, Kim, into oblivion. Something he regularly does with me.

Wait did I also forget that part as well?

Yeah well, my brother and I have an interesting relationship. We are in an incest relationship, yeah we fuck each others brains out.

And it all started when we turned 14. Here we are now at the age of 18. That's right, 18 and I already know that my brother is the love of my life.

Already getting my heart broken, who would have thought.

This is actually all my fault for allowing it to happen and by it I mean our sex life.

Now I bet you are asking yourself, _why the fuck are you still watching them fuck like rabbits Serri??_

Simple, I still think Sehun is gorgeous as he fucks into my best friend. Even if I am doing damage to myself. I know I am crying but I can't help it. It's like I'm in a trance and can't move. It's not until I hear him say something that I wake up from whatever spell I'm on and back up until my back hits the wall. I quickly get out and make my way towards the library.

Why the library? Simple, no one would look for me there. Yeah I'm smart but I never go to the library to study or do homework. I just think it's boring but today not so much. Might be the only place where our mutual friends would never look and hang out.

Yeah we have the same friends, sad isn't?

Once I get to the library, I ask for a room just for myself. They give me a key to one of the private rooms and I make my way there. As soon as I close the door and lock it I start to cry.

Happy Birthday to me I guess.

Oh yeah, today is also our 18th birthday. What a way to celebrate.

Before I get ahead of myself, I should maybe tell you how this all started and why. Which would then explain why it's my fault and how I ended up in the library on my birthday crying.

Strap on your seat belts gang because this is going to be a long and bumpy road.


	2. I

You see it all started a few months after we turned 14. Sehun and I were actually close when we were kids. Best friends. Always doing things together and always being each others back ups. That is until I turn 11. My body started to change and it creeped it out. I hated my breasts and all the hair growing on me. I hated that I was changing and nothing was happening to Sehun. So I did the only thing that made sense to me at that time. 

I ignored him.

He was invisible to me and I know I broke his heart because it was breaking mine to do that to my twin but I had to do it. What if he hated me for changing and not staying the same?

Anyways, he stopped trying after a few months and we just thrifted apart. Of course there would be times that we fought and we fought hard. One time he pushed me down the stairs and I kicked him. I kicked him so hard mom grounded me and they had to take him to the emergency room because well I might have, maybe made him sterile. Did I feel bad? Not one bit, he did push me down the stairs.

So you can only imagine how surprised I was when he came up to me that faithful day and asked me one simple questions.

"Will you have sex with me?"

I looked at him like he was crazy. Just why the fuck would I do that. I turned around and almost went to our parents when he stopped me and told me why. Which honestly, was stupid for me to feel bad for him if you think about it or to even consider it. His reasonings were so fucking stupid. The girl he was crushing on at that time, Irene, wanted to have sex with him because of the rumors going around school. That he was a sex god or whatever.

Irene thought that if she had sex with Sehun she would be seen as a sex goddess. Not only that but she wouldn't be a virgin anymore and would be wanted by her crush who was someone older than us. Sehun obviously said yes for some stupid reason and wanted to practice with me. The only girl he knows that knows about the fake rumors.

Apart from that, he also pitched in that I would then be experienced when we are done. Which at the time was a solid reason. I mean, who wants to be inexperienced while having sex with someone? Definitely not me, that's who.

So with his idiotic reasoning and him telling me I would benefit from it as well, I said yes.

I actually said fucking yes AND we planned it all out to make sure we never got caught. Everything, even to buying condoms and plan b. We planned it to be on our parents anniversary which luckily for us, was next weekend. By now they trusted us to take care of each other and not do anything stupid. When they left we ate food and then watched some tv before getting started. 

Our first fuck session was a disaster. He forgot the put on the condom, came on my tummy before he even went inside of me. I wasn't even turned on, hell I wasn't even naked!! God you would think from the amount of time we had, we would have researched everything. So our second try started a few hours after I had changed into something else then we researched. Watched a few porn videos until we were horny enough.

And god was I horny after watching a porn of a step father fucking his step daughter. The video was filthy and such a turn on. We decided to pick a video to follow. So instead of going hard core, we picked a slow love making one. Perfect for us.

We sat on my bed and left the laptop on my desk table as we watched the couple slowly touching each other and giving each other little kisses here and there. We looked at each other and started to do the same. It was weird at first. I mean we are twins but slowly it started to feel okay. His hands were very gently with me where ever he touched and the way he was kissing me made me feel like a queen and this was only the beginning. We would still watch the couple from the corner of our eyes when we noticed they were taking each others clothes off.

I lifted his shirt off and kissed his chest only to hear him moan. He brought my face to his and for the first time kissed my lips. God I remember that first kiss, it was everything to me. I felt like I was his only one at that moment. I never wanted it to end but it did a few seconds later when he took off my shirt and left me in my pink bra. He kissed each breast and brought my lips to his as he kissed me. I moaned loving how it was all feeling and we weren't even in the main part of it all!

It just felt natural like we belonged somehow. We got lost in the kiss when we realized the couple were almost naked. Quickly we took off our bottoms and did what the couple were doing. The woman was now sitting on the males lap. With her privates on top of his very prominent dick. So I did the same and started to kiss him again. His hands were on my hips, moving me, making me rub into him. Feeling his size, making me drenched in my juices. Our moans were getting louder when I felt him grab my ass and turn me over so now I was laying on my bed. My hips automatically rose to keep feeling him but he pushed me down only for him to look at the tv and see that the couple was now nude.

I bit my lip and whined when I didn't see him move and that's when he asked me if I was sure. I smiled and kissed him. Told him I was 100% positive, we left the video on and just did was naturally came to us. We got naked. He kissed me everywhere, licked me and sucked me. The penetration was horrible. We both felt shy and almost backed out but stopped and kept going. It hurt for a long while that again we almost stopped but I knew deep down this was meant to be so I told him to give it more time and to just kiss me. Eventually the pain died and he started to thrust in and out of me slowly.

I was in heaven. The pleasure of feeling him fill me out of feeling him stretch me out was out of this world. The way I could feel every vein touching my walls was just, I don't even know how to explain it to be honest. I just know that our second time trying was magical. No matter what happens or what the future holds for me, I will never regret our first time. His kisses and touches made me feel real. Like I mattered.

Like he never stopped caring for me. As if he always loved me and never hated me. Even the morning after, the smile he gave me was everything to me. 

Everything just seemed perfect and now, here I was in the library crying my eyes out. With my phone pinning every once in a while from my parents, friends and Sehun.

I hate everything from this day. Everything. After a few more hours, I decided that it was enough to mourn the loss of something I never had. I'm a strong girl and I shouldn't let a boy get to me at all. Especially my brother.

After I get out of the library, I call my parents back to see what they wanted.

"Serri honey! Where are you? We already spoke with Sehun and is grounded for the rest of his life, please come back home" my mom said as I walked towards the bus stop.

"What?"

"Have you been home at all today?"

"No, after I got out of school, I went to the library to work on a paper that is due next week. Why?" I faked.

"Well, we found Sehun doing something in your room. Don't worry! I am washing everything, unless you want to burn it and get new ones which I am totally fine with. Sehun is cleaning your room now as well"

"I'm not sure what you mean mom. What did he do?" I kept faking wanting to know what exactly they caught him doing.

"Baby just come home. We can talk about it here, I just.. I don't know where you are but I don't want to lose you okay? Maybe daddy can pick you up, hes out looking for you, call him"

"Okay mom"

I knew they caught him with Kim, I'm just surprised that they never stopped but then again, maybe they wanted to get caught by me and they just never found out that I did see them. I called my dad and in 3 minutes he picked me up. He stayed quiet through out the whole ride home and wouldn't tell me anything except that he was sorry I had a shitty friend. Which solidified the fact that it was indeed Kim.

As soon as I got home I got a huge hug from mom. I could hear movement from my room as mom took me to the dinning room. She explained everything to me and told me that whatever I wanted I could have. All I wanted was new sheets and for this day to end. I told them I wasn't in the mood for cake or celebration.

Dad went to go get Sehun to go buy me new sheets and blankets out of his own money. Mom told me I could rest on their bed for the time being. 

As I was walking up the stairs to rest, Sehun was making his way down when he saw me. I didn't look at him and just kept looking straight. He tried to grab my hand but I brought my hand to my chest not wanting him to touch me but he had other plans. He followed me to our parents room and closed the door only to grab me and turn me around.

"What do you want Sehun"

"Are you okay? Did mom and dad te-"

"Tell me that you fucked Kim on my bed? Yeah they did, sorry I wasn't there for the show though. Heard it was a real scream"

"Serri, it's no-"

"I don't care. You are free to do whatever you want. We never had a closed relationship. Besides we are siblings and nothing more"

"No! Just lis-"

"Can you go? I want to take a nap"

"Serri, plea-"

"OH SEHUN IF YOU DON'T GET YOUR ASS DOWN HERE RIGHT NOW, I WILL ADD ANOTHER 5 YEARS TO THAT GROUNDING" our father screamed.

"Go"

Just like that our relationship ended. But hell if I wasn't going to make his life a living hell and make sure he felt his heart break into a million pieces.

Get ready Oh Sehun, because the game has just begun. 

**Notes for the Chapter:**

> FIRST CHAPTER SINCE ENDLESS LOVE WILL END SOON!!!!
> 
> At this moment I am not sure if I will have her talking about their past or if I will have chapters dedicated to their past adventures. For those of you that follow me on Asianfanfics would know just how different this story is from what I had originally wrote. I want a drama filled smut fic. So I am trying my best to have that happen.
> 
> I don't know when the next chapter will happen but I hope it will be soon!
> 
> Until next time!!!


	3. II

A week. That's how long it has been since I last talked or even looked at Sehun. That's how long I haven't talked to Kim and that is how long I have been away from my friends and just stayed in the library. As stupid as it sounded, I just didn't want to deal with them. It seemed like they didn't know what Sehun and Kim did. Nor do I care that they know but it seemed like rumors were flying everywhere. Around them and me. Some are horrible others are tame. Either way, I was never going to forgive them and they were going to pay. However, now, I'm just chilling in the library.

I always asked for a private room to eat my snack and never get bothered by anyone. I know, I know 'why not just show them you aren't affected?'. You see I have a plan (well plans) and depending on how long they take to talk to me is which one I will go with. The longer they wait... well the worse it gets.

I'm writing more ideas for certain plans as someone knocks on the door and opens it. I look up and see a short kid entering the room. I've seen him in a couple of my classes but never bothered to learn his name. He was quiet and weird.

"Uh, hi. Umm, I was wondering if I can share this room with you? The other ones are taken and I'm not welcomed in any of them" he said as he pushed his glasses up his nose. Instead of saying anything I just shrugged and went back to my notebook. I could see his shadow close the door and take out his work out of his bag and start working on his homework.

We didn't talk to each other after that. It wasn't till I got a text from Sehun asking where I was that I took notice of the time. I turned off the phone and put it upside down on the table. 

"It's only 4, why is he being a little bitch"

"Excuse me?"

I looked up and found the same kid there looking up at me. I gave him a tight smile before replying back.

"Nothing sorry, just my brother bothering me"

All he did was nod his head and go back to work until there was a knock on the door, we both looked up and saw Hyuna walk-in as she smiled at the kid.

"Here you are! The girls are looking for you, why are you hiding?"

He shrugged and gave her a look, which told me he didn't want me to know. Instead I looked down and closed my notebook getting ready to leave just in case.

"Did she bother you?" I heard her ask him.

"N-No! She let me stay. We just did work" I heard him say as I look up at them both.

I know Hyuna knows who I am. I was always around the popular crowd not to mention I'm Sehun's twin sister.

"I heard your brother is looking for you and shitting his pants. Why are you running away? You guys are always together and close"

"Non of your concern Kim"

"Naw, call me Hyuna. I'm nothing like that fucking bitch you call best friend"

I laughed at her comment as I continued to put my things away and finally put my back on my shoulder, ready to leave.

"That is true, you at least honor your friendship. See ya later" I said and walked towards the door when I heard him speak.

"Wa-Wait!"

I stopped and turned around to look at him.

"I-Is it o-oka-ay for m-m-me to come ba-back to yo-you-your room?"

I smiled at him and answered.

"Just as long as you don't mind me munching on food every once in a while" I waved at them both and left.

____

I had completely changed my room. Instead of bright pink everywhere and looking like an innocent kids room. It was now a grown woman's room. Sophisticated. Everything I wanted since I turned 16. Parents decided to give me $15,000 to spend on just giving my room a makeover after Sehun's little show. My walls were now black with beautiful white trims. Besides the walls, everything was white. My desk, headboard of my bed, dresser and shelves where I keep my books. I had also gotten a few real plants to put around my room, walls and hang them from my ceiling.

I love my new room. Nothing like my old one and I just know it bothers him and I am totally okay with it. It's only phase one of my plan after all.

I was lying on my bed, already showered and ate dinner when I heard a knock coming from my door. I looked at my door and saw my mother walk in. I quickly sat up and gave her my attention.

"Hi baby. I'm just checking on you since you don't seem to be acting normal."

"I mean would you after you find out what your best friend did?"

"But don't you think you are taking it a bit far? Yes what Sehun and Kim did is not right but at the end of the day, if they like each other its only normal for them to get together"

I groaned and went back to laying on my bed.

"That's not the point. Yes they can fuck each ot-"

"Language" she said as she cut me off.

"Sorry. Yes they can have sex with each other but to do it on my bed? They both knew this is my room mom. They knew I would be home sooner or later. It's not like it's Kim's first time in our house or in my room. She has been here countless of times and then there is Sehun mom!! I would never ever do that to him in a million years! I'd never disrespect him like that, especially on his birthday"

"I know honey. I'm just worried about you it all."

"I'll be fine mom, just give me time. It's not everyday you get backstabbed by your best friend and your brother.... who knew his hate for me went that deep"

Mom kissed my forehead and stood up to leave but before she did, she looked back at me with worried eyes.

"Just remember, I am always here for you darling. You can come to me and I will never scream or judge you"

"Thanks mom"

___

The next day I had yet again woke up early and left before he had a chance to tell me he would give me a ride to school. Again I went into the library waving at Miss Parker as I went inside my normal room with my breakfast. There was the kid again. I smiled at him when he looked up and shyly waved back before going back to his work.

This time I started to finish up my homework as I ate food. In a few minutes the door opened again and in came in Hyuna again and sat next to the kid.

"I won't stay long but I need to talk to Serri alone Kyung. Can you wait outside?"

I looked up at him and shrugged. He got up and left us alone. I waited to hear what she had to say.

"Something happened and I'm not the only to take notice. The whole school can see something happened. I don't care to be honest, nor do I want to be your friend. I know you and your type but know that I will be civil with you as long as you are nice to my cousin Kyungsoo. Your brother and friends are a nightmare with him. So to know that at least one person in this damn school that aren't my friends treat him like a human is nice. If you fuck up, I won't hesitate to cut you up"

I don't know why but I started to laugh and cry at the same time. I could hear the door open and someone talking to her in a whispered voice. I calmed myself down and looked at her as I straighten myself.

"You don't have to worry, hell I'll even stand up for him if I see it happen. Something did happen and I am no longer associating myself with them. No longer talking to my twin brother either. Besides I never treated your cousin badly, I've seen him in some of my classes and all I have ever done is ask to borrow a pencil or help him with a math equation."

"Sh-she speaks th-th-the truth. Always nice"

"Good, that means you can meet my other friends. Come in guys"

The door once again opened (I should really learn how to lock the fucking door, tell Kyungsoo to get in the habit of doing it too) and 2 girls walked in.

"This is Krystal and Amber. Both my best friends and will also kick your ass if you do anything to Kyung. Girls this is Serri, she is good"

"Aren't you Sehun's twin?" Amber asked me as I rolled my eyes at her but Hyuna told her that I was still good regardless of who my twin was. After a few more minutes they left the room. Leaving me and Kyungsoo alone. I noticed he was blushing and was not looking up at me. Might as well make a new friend with him but before I could open my mouth and say anything the door opened on its own and Sehun walked in.

I could tell Kyungsoo was scared of him so I stood up and went to the other side.

"What the fuck are you doing with this loser?? I have been calling you non stop trying to see if you made it to school on time!!"

"Oh shut up!! I am obviously fine if mom and dad aren't calling you to tell you other wise."

I could tell he didn't like me going to the other side of the table. Away from him.

"Whatever, we need to talk. Which means get out pussy boy"

"Don't talk to him like that"

"What?"

"You heard me. His name is Kyungsoo and he is my friend so I suggest you leave him alone"

"You are friends with this geek?"

"So what if I am?" I said as I put my hand on Kyungsoo's shoulder to steady him and to let him know I was there for him.

I can see the steam rolling off his head as if it was about to blow. Maybe being friends with Kyungsoo would have its benefits.

"I think I need to teach you a lesson"

"I don't think so. Leave before I call mom and dad and tell them you are bothering me"

"The fuck?"

"Leave Sehun, we are trying to do work"

He smirked at me before looking at Kyungsoo and spitting out his last words.

"This isn't over fucker, I will get to you"

He left the door and slammed the door shut.

"Well" I said as I walked over to the other side and looked at him. "That could have gone better, don't ya think"

And just like that we both laughed and noticed that this was a friendship that would last a lifetime.

**Notes for the Chapter:**

> Starting out slow. There will be multiple flashbacks as the story continues. I want you guys to see how she changed from just that one incident. Obviously this runs deeper and its not just about Kim and Sehun fucking on her bed. I'm so excited for this!!!!  
> See you guys next weekend!!


End file.
